When deploying wireless communication networks, there is a balance between coverage and capacity. On the one hand, a few large cells can provide great coverage but at a cost of reduced capacity. On the other hand, a scenario with many small cells creates better capacity and throughput, but may not provide the desired coverage. Hence, there is often a combination of larger cells to provide sufficient coverage with smaller cells to provide better capacity.
However, when the cells get too small, wireless terminals moving in the network cause a great number of handovers which causes significant overhead. Moreover, providing coverage indoors using many small cells can be quite costly, with a radio base station for each such small cell.
One solution to this problem is to use remote radio heads, where several remote radio heads connected to the same radio base station share the same cell. In this way, a single radio base station can provide coverage in different parts of the building by placing the remote radio heads appropriately. Moreover, the wireless device can move between the coverage of different remote radio heads while staying within the same cell, thus avoiding causing handovers. The wireless device will not realize that it is served by different remote radio heads, but see it as one single cell.
However, since only one cell is spanned by multiple remote radio heads, the granularity of location determination of a wireless device by cell identification is quite large. This leads to insufficient positioning accuracy in locating wireless devices, leading to issues in complying with increased accuracy of positioning requirements for emergency calls such as those specified in Enhanced-911 (E911) by FCC CSRIC (Federal Communication Commission Communication, Security, Reliability, Interoperability Council). Moreover, since the remote radio heads are often deployed indoors, satellite based positioning such as GPS (Global Positioning System) is often unavailable.